Methods and apparatuses for reducing interference using frequency division multiple access

ABSTRACT

Methods, systems, and apparatuses are described which are capable of mitigating interference between piconets. Devices on a piconet may detect a certain degree of interference. When this interference is deemed as arising from another piconet, the first piconet may cease transmitting on a set of bands while the interfering piconet may continue to transmit on this set of bands. Furthermore, the interfering piconet may cease transmitting on another orthogonal set of bands within the frequency spectrum while the original piconet continues to utilize these bands. Transmission on these sets of bands may be resumed after a predetermined time period. In this manner interference between the two piconets may be minimized.

RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C. § 119(e) to U.S.Patent Application Nos. 60/419,459 entitled “Apparatus and RelatedMethods for High-Data Rate Communications” filed on Oct. 17, 2002;60/424,642 entitled “Apparatus and Related Methods for High-RateCommunications” filed on Nov. 7, 2002; 60/432,435 entitled “Apparatusand Related Methods for High-Data Rate Communications” filed on Dec. 11,2002; and 60/451,560 entitled “System and Method for Multi-band UWBRadio Communications” filed on Mar. 3, 2003. This application is relatedto U.S. patent application Ser. No. ______ (Attorney Docket No.ALER0001), entitled “Methods and Sets of Piconets Using Time FrequencyDivision Multiple Access” filed on the same date as this application.All patent applications referenced in this paragraph are fullyincorporated herein by reference.

TECHNICAL FIELD

[0002] The present invention generally relates to piconets, and morespecifically to methods, computer programs, and piconets using differentfrequency bands within a frequency spectrum used for time frequencydivision multiple access.

DESCRIPTION OF THE RELATED ART

[0003] Efforts have been underway to develop wireless Personal AreaNetworks (“PANs”), a network of devices communicating data. Contention(two different devices in different PANs trying to communicate at ornear the same frequency) and interference problems (other noisesources), collectively, “interference,” where communication to or fromeither or both devices affects the quality of signal sent or received byeither or both devices. Co-locating multiple PANs may require asignificant amount of coordination; however, such coordination may beundesired.

[0004] One attempt to solve these problems is to use notch filters toexclude frequencies where known competing systems operate. Anotherattempt to solve the problems is to employ a frequency-notched antenna.Both of these attempts add to the complexity of a radio device.Moreover, these attempts to solve the problems result in a radio that iscompatible only with the radio-frequency (“RF”) environment for which itwas designed. In other words, a change in RF environment mightnecessitate a design change for the notch filter or thefrequency-notched antenna.

SUMMARY

[0005] A set of piconets, methods of establishing and using them, andcomputer programs for carrying out at least a portion of those methodsmay help to reduce contention time between piconets. In one embodiment,a seven-length code architecture may be used with one or more groups ofbands so that contention time cannot exceed {fraction (1/7)} of the timetimes the number of group(s) of dwell times. Up to seven different bandscan be assigned to each group of dwell times. When less than seven bandsare used (e.g., three or six), at least one of the bands may be assignedto more than one dwell time. Alternatively, each dwell time within thetime span may be assigned to a different band. The state may be changedas needed or desired. Using either scheme (repeated bands within a codeor changing states), a prime-number architecture can be used with anon-prime number of different bands can be used.

[0006] Furthermore, methods and apparatuses for the mitigation ofinterference between piconets are depicted. These methods andapparatuses allow a device on a piconet to detect interference,characterize this interference, and the device or piconet to takeappropriate action to ameliorate this interference. In many embodiments,interference between two piconets may be detected, and one or more ofthe devices on one of the piconets may cease transmitting on a set ofbands while the other piconet continues to utilize these bands.

[0007] Additionally, electronic media are presented which embody thistype of methodology in computer systems, hardware, and software thatmitigates interference between piconets.

[0008] In one set of embodiments, a set of piconets can comprisepiconets. Each piconet can have a unique code compared to the otherpiconets in the set of piconets. Each unique code corresponds to asequence of dwell times and bands. During a time span, any two differentpiconets in the set of piconets are capable of using one or more samebands for a collective time for each group of dwell times, no longerthan the longest dwell time within such group of dwell times.

[0009] Another aspect of the present invention can comprise a method ofestablishing a set of piconets. The method can comprise generating a setof codes similar to those described above and assigning the codes to thepiconets.

[0010] In another set of embodiments, a set of piconets can comprise afirst piconet and a second piconet. Within the set of piconets, thefirst piconet has a first code corresponding to a first sequence ofdesignated bands, and the second piconet has a second code thatcorresponds to a second sequence of designated bands. At least one bandmay be present in the first sequence that is not present in the secondsequence.

[0011] In still another aspect of the present invention, a method ofusing a set of piconets comprising the first piconet. Each piconet inthe set of piconets may have a unique code compared to the otherpiconets. Each of the unique codes can correspond to a sequence of dwelltimes and bands including the first band, wherein the sequence includesat least one group of dwell times. The method can comprise changing astate of the first band. The state may be changed from a designatedstate to an undesignated state, or vice versa.

[0012] In a further set of embodiments, a piconet can comprise a codethat corresponds to the utilization of different bands during a timespan of seven dwell times. In yet another further aspect, a method ofthe using the piconet can comprise assigning the code to a device withinthe piconet and communicating to at least one other device within thepiconet using the code.

[0013] In still a further aspect, portions or any or all of the methodsmay be implemented using a computer program. The computer program cancomprise a computer-readable medium adapted to execute instructions whenthe computer program is run on a computer.

[0014] In one set of embodiments, one or more devices on a secondpiconet cease transmitting on a second set of bands while the firstpiconet continues to utilize this second set of bands.

[0015] In one set of embodiments, ceasing transmission on the first setof bands is done for a predetermined time period.

[0016] In one set of embodiments, the first set of bands and the secondset of bands are substantially orthogonal.

[0017] In one set of embodiments, a packet error rate is evaluated todetermine if interference is present.

[0018] In one set of embodiments, the first set of bands is monitored bythe first piconet.

[0019] In one set of embodiments, transmission is resumed by one or moredevices on one or more of the bands if no activity is detected withinthe first set of bands.

[0020] The foregoing general description and the following detaileddescription are exemplary and explanatory only and are not restrictiveof the invention, as defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is illustrated by way of example and notlimitation in the accompanying figures.

[0022]FIG. 1 includes an illustration including two piconets, each ofwhich includes a plurality of devices that can communicate to oneanother within its particular piconet.

[0023]FIG. 2 includes an illustration of a frequency spectrum separatedinto frequency bands.

[0024]FIG. 3 includes illustrations of baseband and passband waveformswhen using Orthogonal Frequency Division Multiplexing (“OFDM”).

[0025]FIG. 4 includes an illustration of a passband waveform when usingOFDM for three consecutive dwell times.

[0026]FIG. 5 includes a table codes for different sequences of thefrequency bands from FIG. 2.

[0027]FIGS. 6 and 7 illustrates exemplary potential timing differencesbetween Code 1 and Code 2.

[0028]FIGS. 8 and 9 include tables of codes illustrating frequency bandsthat are in designated or undesignated states.

[0029]FIG. 10 includes an illustration of a frequency spectrum separatedinto two groups of frequency bands.

[0030]FIG. 11 includes a table codes for different sequences of thefrequency bands from FIG. 10.

[0031]FIGS. 12 and 13 include tables of codes illustrating frequencybands that are in designated or undesignated states.

[0032] FIGS. 14-16 include illustrations of a seven-length architectureusing 7, 6, or 3 different bands to generate a code for a piconet.

[0033]FIG. 17 is a physical representation of the overlappinggeographical areas covered by two piconets.

[0034]FIG. 18 is a flowchart depicting an embodiment of a method formitigating interference between piconets.

[0035]FIG. 19 is another physical representation of the overlappinggeographical areas covered by two piconets

[0036]FIG. 20 is an illustration of a universal band sharing policy forpiconets.

[0037]FIG. 21 is a message sequence chart depicting negotiated bandallocation between a device and a piconet.

[0038]FIG. 22 is a message sequence chart depicting a device bandcoordinating within its piconet.

[0039]FIG. 23 is a message sequence chart depicting device initiateddisassociation with a piconet; and

[0040]FIG. 24 is a message sequence chart depicting device initiatedassociation with a piconet.

[0041] Skilled artisans appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to help toimprove understanding of embodiments of the present invention.

DETAILED DESCRIPTION

[0042] Reference is now made in detail to the exemplary embodiments ofthe invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts (elements).

[0043] A set of piconets, methods of establishing and using them, andcomputer programs for carrying out at least a portion of those methodsmay help to reduce contention time between piconets. In one embodiment,a seven-length code architecture may be used with one or more groups ofbands so that contention time cannot exceed {fraction (1/7)} of the timetimes the number of group(s) of dwell times. Up to seven different bandscan be assigned to each group of dwell times. When less than seven bandsare used (e.g., three or six), at least one of the bands may be assignedto more than one dwell time during a time span. Alternatively, dwelltime may be assigned to a different band. The state may be changed asneeded or desired. Using either scheme (repeated bands within a code orchanging states), a prime-number architecture can be used with anon-prime number of different bands.

[0044] Before proceeding further, some terms are defined or clarified.As used herein, the term “band” is intended to mean a frequency band.

[0045] The term “contention” is intended to mean two or more devices aretransmitting at the same or similar frequency such that a receivingdevice has difficulty receiving or understanding a transmission from itscorresponding transmitting device.

[0046] The term “designated” is intended to mean a state of a band inwhich a piconet currently can communicate in the set of piconets usingthat specific band. A band in a designated state may also be referred toas being on or active. The band may be in a designated state for theentire set of piconets or only for specific piconet(s) within the set,only for specific device(s) within a piconet, or combinations ofindividual piconet(s) and device(s).

[0047] The term “dwell time” is intended to mean a time period within atime span. Dwell time may also be referred to a “symbol.”

[0048] The term “interference” is intended to mean signals, regardlessof source that makes receiving or understanding a transmission from atransmitting device more difficult. Interference includes contention andnoise.

[0049] The term “noise” is intended to mean signals from any sourceother than a device in a neighboring piconet. Examples can include amicrowave oven, a vacuum cleaner, or the like.

[0050] The term “optical signals” is intended to mean signalscommunicated over a wireless communicating medium at a frequency of atleast one terahertz (“THz”). One terahertz equals 10¹² hertz. Note thatsignals communicated over a wireless communicating medium within theultraviolet range and higher frequencies outside the visible lightspectrum are considered optical signals for the purpose of thisspecification.

[0051] The term “RF signals” is intended to mean signals communicatedover a wireless communicating medium at a frequency less than one THz.

[0052] The term “time span” is intended to mean a sum of the dwell timesduring which a piconet may communicate using a sequence of bands beforerepeating the sequence.

[0053] The term “undesignated” is intended to mean a state of a band inwhich a piconet currently cannot communicate using that specific band. Aband in an undesignated state may also be referred to as being off orinactive. The band may be in an undesignated state for the entire set ofpiconets or only for specific piconet(s) within the set, only forspecific device(s) within a piconet, or combinations of individualpiconet(s) and device(s).

[0054] As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

[0055] Also, use of the “a” or “an” are employed to describe elementsand components of the invention. This is done merely for convenience andto give a general sense of the invention. This description should beread to include one or at least one and the singular also includes theplural unless it is clear that it is meant otherwise.

[0056] Before addressing specific implementation details, a relativelyhigh-level description is given regarding a set of piconets and itsoperation. A frequency spectrum may be separated into bands. All ofthose bands may be within one or more groups of bands. The frequenciesfor the bands may be chosen to enable a multiple mixer type ofsynthesis.

[0057] Some or all of the bands within the frequency spectrum may beused for relatively high data rate transmissions between devices withina piconet. One or more bands within the frequency spectrum may need tobe dedicated or reserved for other purposes (e.g., low data ratetransmissions, regulatory requirements, etc.) (hereinafter, collectivelyreferred to as “reserved bands”). The reserved band(s) may lie betweenany of the bands for high data rate communications or at either or bothends of such high data rate communication bands. For the purposes ofthis specification, the piconet will be addressed using bands of thefrequency spectrum for high data rate communications, and does notinclude the reserved bands.

[0058] In one embodiment, a time span may include one or more groups ofdwell times. The number of dwell times (“p”) within each group of dwelltimes may be equal to the number of possible bands for the high datarate transmissions. In one embodiment, p is a prime number. When morethat one group of dwell times is used, the groups can have the same ordifferent prime numbers of dwell times. Within a group of dwell times,the number of possible piconets that can be supported within a set ofpiconets may be p−1.

[0059] Unique code sequences can be generated for the piconets bygenerating a different sequence of band utilization during differenttime periods. The codes may correspond to the sequence in which thebands are used during a time span. When p is a prime number, two or moredevices may contend for the same band no longer than the longest dwelltime within for each group of dwell times. The bands may be part of asingle group or divided between two or more groups. Each group may havea prime number of bands. In one embodiment, the sequence of bandsassigned to each piconet may be generated using a linear congruentialtechnique.

[0060] Dwell times within a time span may be equal to one another. Equaldwell times can be easier to implement within devices, so that eachfrequency is used for approximately the same length of time during onetime span. The pulse rate can be substantially equal to 1/(dwell time).Contention time (time that any two different devices are competing forthe same band) may be one dwell time (1/p times the time span) for agroup of dwell times. In another embodiment, dwell times of differentlengths may be used. For example, in a single group of bands, a firstdwell time may be 1.5 times longer than a second dwell time, a thirddwell time may be 1.2 times longer than the second dwell time, and therest of the dwell times during the time span are the same length as thesecond dwell time. The longest contention time during a time span forthis embodiment is no greater than the longest dwell time for the timespan, which in this embodiment, is the time length of the first dwelltime.

[0061] The bands may be any frequency, so long as, at a specific band,interference caused by immediately adjacent band(s) is at a level thatdoes not significantly interfere with communications at the specificband. If interference is too great, the bands may need to be spacedfurther apart. In one embodiment, the use of individual bands within thefrequency spectrum and the codes described herein coupled with multibandcan yield a piconet to piconet isolation of 7 to 1, which in turntranslates to approximately 8.5 dB in amplitude or 17 dB in power codeisolation between bands.

[0062] The band separation between each pair of adjacent bands (centerto center) within the spectrum may be equal to or a multiple of thesmallest band separation when the spectrum has three or more bands. Whenthe band separations between each pair of adjacent bands are equal to ormultiples of the smallest band separation, fewer oscillators may be usedin the devices in the piconets, and may be at little as one oscillator.In one embodiment, the band separation may be at least 400 MHz. Smallerband separations may be used if desired. In another embodiment, bandseparation between bands may not be equal to or a multiple of a singlefrequency. Also, the bands may or may not be contiguous with other bandsin the frequency spectrum. In other words, a gap in frequency may liebetween two neighboring bands and will be described in more detail laterin this specification.

[0063] Each device may communicate within its piconet using up to pbands. However, in one embodiment, using all p bands for a specificpiconet may not be desired for any number of reasons. Therefore, thepiconet may use fewer than all p bands. The piconet may use a number ofbands in a designated state (“n”), which may be an integer from 1 to p.The piconet may have other band(s) in an undesignated state, if any. Thenumber of undesignated bands can be equal to p−n, which may have integervalues from 0 to p−1. Note that a specific band may be in a designatedstate or undesignated state for one, some, or all piconets within theset of piconets. Also, the states within one piconet or other piconetsfor one, some, or all devices can be changed between the states.

[0064] Attention is now directed to details of non-limiting embodiments.In FIG. 1, set of piconets (“set”) 100 includes piconet 120 and piconet140, each of which includes a plurality of devices. Other piconets maybe present within set 100 but are not shown in FIG. 1. An example of apiconet is a Personal Area Network (“PAN”). A PAN is smaller than aLocal Area Network (“LAN”), which is in turn smaller than a Wide AreaNetwork (“WAN”). The set 100 may be located in the same building, and inone embodiment, each piconet may be located within an office or cubicle,and the piconets may be located in adjacent offices or cubicles on thesame or adjacent floors (levels) of the building. Each piconet withinset 100 may be less than 100 meters away from its nearest neighboringpiconet, and in one embodiment may be separated by less than a meter(e.g., a wall or partition). Note that the geographic configurationsdescribed in this paragraph are exemplary and not limiting. Afterreading this specification, skilled artisans will appreciate that anearly limitless number of other geographic configurations are possible.

[0065] Devices within piconet 120 include laptop computer 120, printer124, and personal digital assistant (“PDA”) 126, and devices withinpiconet 140 include laptop computer 140, printer 144, scanner 146, andcamera 148. Other devices (pagers, cell phones, etc.) could be used.Although each device in piconets 120 and 140 are shown to have externalantennas, such external antennas are not required but are shown toillustrate communication between devices using a wireless communicatingmedium. Each of the devices may include a transceiver, a receiver, or atransmitter. Any combination of devices within piconet 120 or 140 may bebi-directionally coupled to each other within the same piconet.

[0066] Each of the devices in piconets 120 and 140 may include one ormore of a central processing unit (“CPU”), read-only memory (“ROM”),random access memory (“RAM”), hard drive (“HD”) or storage memory, andinput/output device(s) (“I/O”), such as a transmitter, receiver,transceiver, or other I/O device, such as a keyboard, monitor, printer,electronic pointing device (e.g., mouse, stylus, trackball, etc.), orany combination thereof. Each of the devices in FIG. 1 may have morethan one CPU, ROM, RAM, HD, I/O, or other hardware components.

[0067] Portions of the methods described herein may be implemented in acomputer program comprising a computer-readable medium adapted toinclude instructions to be executed when the computer program is run ona computer. The computer-readable medium can include ROM, RAM, or HD ofthe device(s). In addition to those types of memories, the computerprogram may be contained on a data storage device, which may also be acomputer-readable medium with a different device. Alternatively, theinstructions may be stored as software code elements on anothercomputer-readable medium, such as a DASD array, magnetic tape, floppydiskette, optical storage device, or other appropriate storage device.

[0068] In an illustrative embodiment, the computer-executableinstructions may be lines of assembly code, compiled C⁺⁺, Java, or otherlanguage code. Other architectures may be used. For example, thefunctions of any one of the devices may be performed by a differentdevice shown in FIG. 1. Additionally, a computer program or its moduleswith such code may be embodied in more than one data processing systemreadable medium in more than one device.

[0069] Communications between any of the devices in FIG. 1 may beaccomplished using RF signals. During any one or more of thecommunications, data may be transmitted to or received from any one ormore devices. For example, when a user is at laptop computer 122, laptopcomputer 122 may convert the signals to a human understandable form whensending a communication to the user and may convert input from a humanto appropriate RF signals to be used by laptop computer 122 or PDA 126.Similarly, when an operator is at PDA 126, PDA 126 may convert thesignals to a human understandable form when sending a communication tothe operator and may convert input from a human to appropriate RFsignals to be used by devices 122 or 126.

[0070] Additionally, any one or more of the devices in FIG. 1 may usemore than one communicating medium. For example, laptop computer 122 mayuse RF communications with devices within piconet 120 but may use awired ethernet connection to communicate to devices connected to a LAN,some of which may or may not be shown in FIG. 1. For example, computers122 and 142 may be part of the same LAN and communicate to each otherusing electronic signals over a wired ethernet connection, rather thanby RF signals used by their respective piconets.

[0071] Returning to FIG. 1, within set 100, contention by two differentdevices in different piconets should be kept relatively low. The codingscheme and method of using the coding scheme are described below to helpreduce the interference problems. The embodiments described herein areuseful for Ultra-Wide Band (“UWB”) applications, but are not limited toUWB.

[0072] Attention is now directed to a non-limiting example withreference to FIGS. 1-3. A spectrum of frequencies can be separated intoa single group of seven different bands numbered 0-6 in FIG. 2. In thisembodiment, the seven bands are equal in size (frequency range) and arecontiguous (no gaps) between neighboring bands. In one embodiment, eachof the bands may be approximately 500 MHz wide when used with UWB. If aband is too narrow, interference from adjacent bands may be too high. Asthe width of the band increases, the number of bands available withinthe frequency spectrum decreases, thus increasing the potentialcontention time between devices in different piconets. After readingthis specification, skilled artisans can choose the size of band thatbest fit their specific application.

[0073] Embodiments of the invention may be used for Orthogonal FrequencyDivision Multiplexing (“OFDM”). FIG. 3 includes illustrations ofbaseband and passband signals during a dwell time. For the upperillustration in FIG. 3, the waveform is illustrated as it appears at theoutput of an Inverse Fast Fourier Transform (“IFFT”). The output isreferred to as a baseband transform because it has not yet been mixedwith a carrier frequency. The lower illustration is for a passbandwaveform and illustrates the baseband waveform after it has been mixedwith a carrier frequency. Mixing can be accomplished by multiplying thebaseband waveform (upper illustration) by a sine wave at a predeterminedfrequency, which for this specific embodiment is 3.25 GHz.

[0074] Continuing with OFDM, different frequencies may be used duringdwell times to produce the passband waveform as illustrated in FIG. 4.Each portion of a baseband waveform for three consecutive dwell timesmay be mixed with different carrier frequencies for the threeconsecutive dwell times (illustrated by the dashed lines) to produce thepassband waveform in FIG. 4. More specifically, Frequency 1 is used asthe carrier frequency during a first dwell time, Frequency 2 is used asthe carrier frequency during a second dwell time, and Frequency 3 isused as the carrier frequency during a third dwell time. Each ofFrequencies 1, 2, and 3 may correspond to different bands.

[0075] Time/frequency sequences can be generated for up to six piconetsin the set 100 to form Codes 1-6 as shown in FIG. 5. Dwell times (t₀,t₁, t₂, etc.) for a time span are identified near the bottom of FIG. 5.The dwell times may be on the order of 3 ns, 30 ns, or 300 ns. The pulserates are the inverse of dwell times and may be on the order of 3 MHz,30 MHz, or 300 MHz. In alternative embodiments, dwell times and pulserates may be less than or greater than those described above. In thisexample, all the dwell times are substantially equal to one another.

[0076] Referring to the first line of the table in FIG. 5, Code 1 can beassigned to piconet 120. Assuming all bands for all devices in the tableare in a designated state, during dwell time t₀, devices within piconet120 can use band 0, and during dwell time t₁, devices within piconet 120can use band 1. During the subsequent dwell times, bands 2, 3, 4, 5, and6 can be used by piconet 120 in that sequence. Code 2 can be assigned topiconet 140. During dwell time t₀, devices within piconet 140 can useband 0, and during dwell time t₁, device(s) within piconet 140 can useband 2. During the subsequent dwell times, bands 4, 6, 1, 3, and 5 areused by piconet 140 in that sequence. The band sequences in the otherlines for other parts are illustrated in FIG. 5. The sequences can berepeated any number of times during subsequent time spans.

[0077] For any code shown in FIG. 5, device(s) in a piconet willpotentially contend with other device(s) in another piconet during nomore than one time during one time span for a group of dwell times,which in this example is approximately {fraction (1/7)} of the time.Referring to FIG. 5, the devices in set 100 may contend for band 0during t₀. However, the devices in different piconets do not contend forsame band during t₁-t₆.

[0078] In practical applications, device(s) in piconet 120 and device(s)in piconet 140 may not turn on at the same time. For example, piconet140 (Code 2) may be turned on after piconet 120 (Code 1 as illustratedin FIG. 6). When piconet 140 turns on, it may start at t₀ while piconet120 is already at t₁. In another words, Code 2 is shifted one unit tothe right. Therefore, t₁ of piconet 120 occurs at substantially the sametime as t₀ of piconet 140. While piconet 120 is at t₀ during the nexttime span, piconet 140 will be at t6. As can be seen in FIG. 6, piconets120 and 140 contend for band 2 during substantially the same timeperiod.

[0079]FIG. 7 is similar to the embodiment described with respect to FIG.6 but illustrates a variation. In FIG. 7, piconet 140 may not be turnedon at an even increment with respect to piconet 120's time spectrum. Forexample, piconet 140 may be turned on ¾ of the way through piconet 120'st₀. In this embodiment, piconets 120 and 140 contend for band 0 for ¼ ofa dwell time and contend for band 2 for ¾ of a dwell time. Therefore,two piconets may contend for more than one band during a single timespan. However, collectively, the time of contention during a length oftime corresponding to single time span does not exceed the longest dwelltime. Because each of the dwell times has substantially the same lengthin this embodiment, the contention time per time span is approximatelythe dwell time.

[0080] Due to a variety of reasons, a piconet or specific device(s)within a piconet may be having problems communicating over a specificband. For example, camera 148 in piconet 140 may contend withcommunications on band 6 within piconet 120. Alternatively, otherradiation sources (e.g., a microwave oven), electromechanicalapparatuses (e.g., a vacuum cleaner), or other noise source may beinterfering with piconet 120.

[0081] In one embodiment, all piconets in set 100 may be having problemscommunicating using band 6. Effectively, band 6 cannot be used by any ofthe piconets in set 100. Referring to FIG. 8, the state of band 6 ischanged from a designated state to an undesignated state for allpiconets within set 100. As illustrated in FIG. 8, bands in theundesignated state have a diagonal line through them, and bands in thedesignated state do not have the diagonal line. Data that wouldotherwise be transmitted over band 6 will be shunted to the nextavailable time period. Referring to piconet 140, its devices maycommunicate at all times except at t₃. Communications that wouldotherwise be transmitting data using piconet 140 using band 6 during t₃are delayed and transmitted using piconet 140 on band 1 during t₄. Notethat the seven discrete dwell time architecture remains intact, andtherefore, no more than one contention time occurs with another piconetin the set 100 during a time span. However, devices in piconet 140 donot have any communications within the piconet 140 during t₃. Thus, thepiconet is configured to allow relatively high data rate transmissionswithout contention time greater than one dwell time per time span groupof bands.

[0082] In an alternative embodiment, a new band is substituted for anexisting band if interference is too great on that existing band. Forexample, band 7 (extra band) may be substituted for band 6 (existingband). Referring to FIG. 8, all occurrences of band 6 are replaced byband 7. In one implementation, band 7 may be an extra band. If a band ina designated state, such as band 6, and it needs to be changed to anundesignated state, then band 7, which may orginally be in anundesignated state is changed to a designated state. After a set time orinterference is at an acceptably low level, band 6 may be substitutedfor band 7. Alternatively, band 6 may now become the extra band and willbe substituted for another band when that other band changes from adesignated state to an undesignated state. Before the substitution, thecode may correspond to band 6 and not band 7, and after thesubstitution, the code may correspond to band 7 and not band 6. Theability to substitute extra bands for existing bands is another novelaspect that helps to keep data transmission rates high while keepingcontention relatively low.

[0083]FIG. 9 illustrates another embodiment, where more than one bandmay be changed from the designated to the undesignated state. Forexample, bands 1, 3, 4, and 6 may be changed from a designated state toan undesignated state. Data that would otherwise be transmitted over thebands in the undesignated state are shunted to other bands in thedesignated state (bands 0, 2, and 5).

[0084] At a later time, one or more of the bands in the undesignatedstate in FIGS. 8 and 9 may be changed from the undesignated state to thedesignated state. As more bands are in a designated state, data ratesfor the communications within the piconet(s) increases. Command(s) tochange between designated and undesignated states may originate withinthe device where such change is taking place or from a command centerfor the piconet. For example, laptop computer 122 may be a commandcenter and a device within piconet 120. Alternatively, a separate,dedicated command center (not shown) for piconet 120 may be used.Alternatively, changes in state may be performed manually. For example,dip switches or a ROM integrated circuit may be changed to affect thechanges in state.

[0085] The bands within a device or piconet may originally be in adesigned state, an undesignated state, or a combination thereof (atleast one band originally in a designed state and at least one otherband in an undesignated state).

[0086] The states of the bands may be changed as circumstances warrant.For example, referring to FIG. 8, band 6 may be changed from anundesignated state to a designated state after a set time period (aminute, an hour, a day, a week, or nearly any other time period). If theinterference in band 6 is still unacceptably high, band 6 may again bechanged from a designated state to an undesignated state. Alternatively,a piconet (via a command center or other device) may monitor theinterference level from interference on band 6 while it is in theundesignated state. After the event has been terminated (e.g., microwaveoven or vacuum cleaner turned off) and the interference level frominterference on band 6 is reduced to an acceptable level, band 6 may bechanged from an undesignated state to a designated state. Note that aset time period may not be used to determine when the state should bechanged if the interference level is being monitored. A combination ofthe two may also be used. In other words, the interference level on band6 may be monitored occasionally (e.g., every minute, every hour, etc.)rather than substantially continuously (e.g., at least one per second)while in the undesignated state and when the interference level isreduced to an acceptable level, band 6 may be changed from theundesignated state to the designated state.

[0087] A frequency spectrum may be separated into more than one group ofbands due to reasons unrelated to the present invention. The groups ofbands may be used during corresponding groups of dwell times. In oneembodiment, a frequency spectrum may be separated into 16 bands, ofwhich, two bands are reserved bands (not shown in FIG. 10). Therefore,14 bands may be used for high data rate communications within thepiconet. The 14 bands may be separated into two groups of seven bands asillustrated in FIG. 10. In one embodiment, each group of bands and dwelltimes may have prime number(s). In another embodiment, the groups mayhave dissimilar number of bands or dwell times. The reserved bands (notshown in FIG. 10) may lie between any of the bands shown in FIG. 10. Inone embodiment, a reserved band may lie between band 6 and band 0′.After reading this specification, skilled artisans will appreciate thatthe reserved band(s) may be located between other bands or near the endsof the bands in FIG. 10.

[0088]FIG. 11 illustrates different code sequences for Codes 1-6. Inthis embodiment, the demarcations of the groups of bands and dwell timescan be seen. One group of bands (bands 0-6) may be used during one groupof dwell times (t_(0′)-t_(6′)). In this design, each of the six piconetshas more RF bandwidth available for transmission, resulting in morereliable transmission of information. Although not shown, the bands fromthe different groups may be interspersed with one another within thecode sequence. Alternatively, the groups of bands may be switched forthe specific code. For example, Code 1 may use bands 0′-6′ during t₀-t₆and bands 0-6 during t_(0′)-t_(6′), whereas the rest of the codes inFIG. 11 remain unchanged. Devices within piconets 120 and 140 may beconfigured for both groups. Any or all of the piconets or devices withina piconet may be reconfigured for only one group, and may bereconfigured at a later time for one or both groups of bands and dwelltimes. The manner for configuring and reconfiguring can be performedusing methods similar to those described with respect to changing statesof the bands (designated state versus undesignated state).

[0089] In an alternative design, each of the six piconets cah transmit asignal simultaneously on the bands k and k′ of FIG. 10, where k is 0, 1,2, 3, 4, 5, and 6; and k′ is 0′, 1′, 2′, 3′, 4′, 5′, and 6′. In effect,dwell times tk and t_(k′) occur simultaneous in this embodiment. In thisdesign, higher rates of data transmission are enabled by thesimultaneous transmission of signals. The ability to communicate withina piconet using two or more bands simultaneously is believed to a novelaspect that allows raw data rates over 1 gigahertz (GHz) to be achieved.

[0090] Still another design using the bands of FIG. 10 enables up to 12piconets by assigning codes 1 through 6 of FIG. 5. to the first sixpiconets, while assigning codes 1′ through 6′ to the last six piconets,where code k′ is obtained from code k by substituting the frequencybands from Group B in FIG. 10 for the corresponding bands in Group A.For example, code 3′ would be the sequence 0′, 3′, 6′, 2′, 5, 1′, 4′.

[0091] Although two groups of bands and dwell times are described, moregroups can be used. The maximum contention time per time span may be sumof the longest dwell times for each group. If all dwell times aresubstantially equal, the maximum contention time per time span can bethe product of the number of groups times the dwell time.

[0092] Similar to the embodiments with one group (FIGS. 6 and 7), bandsmay be in designated and undesignated states. FIG. 12 includes anillustration where bands 0-6 and 0′-2′ can be in the designated stateand bands 3′-6′ can be in the undesignated state. Therefore, each devicemay communicate using 10 bands. FIG. 13 includes an illustration wheremost piconets can use up to 12 bands. All bands for most piconets aredesignated except for 1 and 5′. Therefore, bands from different groupsmay be in the undesignated state. Also, note that the piconets for Codes2 and 3 may have band 3′ in the undesignated state. This embodimentillustrates that bands for individual piconets (codes) may be in theundesignated state while the same band in other piconets in set 100 maybe in a designated state.

[0093] Many other embodiments of the present invention may be possible.A piconet may use a code that corresponds to the utilization ofdifferent bands during a time span of seven dwell times as seen in FIGS.14-16. In one embodiment, seven different bands may be used once duringeach of the dwell times in a time span as illustrated in FIG. 14. Notethat this code sequence is the same as Code 1 as illustrated in FIG. 5.One, some, or all devices within the piconet can use the same code.

[0094] In another embodiment, only six different bands (0-5) are usedwith the seven-length code architecture as illustrated in FIG. 15. Notethat band 0 is used during two different dwell times (t₀ and t₆). Instill another embodiment, only three different bands (0-2) are used withthe seven-length code architecture as illustrated in FIG. 16. Note thatband 0 is used during three different dwell times (t₀, t3, and t₆), andband 1 and 2 are used during two different dwell times. An advantage ofthis embodiment, compared to changing states of bands between designatedand undesignated states, is that communications may be substantiallycontinuous during a time span. However, the number of neighboringpiconets may be limited or contention time may increase. Designers,users, or both of such piconet(s) may be able to configure piconet(s) tomeet their particular needs regarding contention time and data rates(e.g., choose between changing states or using a smaller number ofdifferent bands within the seven-length code architecture.

[0095] Embodiments described herein may allow users of set 100 toachieve advantages over conventional systems. For one group of bandswithin any time span, the contention time between devices in any pair ofpiconets in set 100 per time span per group of bands and dwell times maybe as little as 1/p, where p is the number of dwell times in a timespan. The set of piconets may support up to p−1 piconets and still haverelatively low contention time.

[0096] Another advantage is that uncoordinated piconets may be used. Inother words, an overriding coordinating architecture does not need to beused for different piconets or between different devices within one ormore piconets. Piconet(s) and device(s) may be added or removed withrelative ease. When a device is added or removed, the change may betransparent to the other devices within the same or other piconets. Suchchanges may be made without substantially adversely impacting the otherdevice(s) or piconet(s) and obviates the need for coordination betweendifferent piconets, devices, or both. Still, if a user desired, piconetsmay be coordinated with one another, if desired.

[0097] Band utilization for set 100, individual piconet, or individualdevice is highly flexible. Individual bands for a piconet or device maybe in a designated state or undesignated state. A band may be changedfrom a designated to an undesignated state for any number of reasons.The change in state may allow better data transmissions to occur withoutas much contention, noise, or other interference from other piconets,devices, or other sources. The state may subsequently be changed to adesignated state after a set time period or after the event causingcontention, noise, or other interference terminates. Such an embodimentallows the number of bands in the designated state to remain relativelyhigh.

[0098] A piconet or device may be configured for nearly any number ofgroups of bands. The piconet or device may be reconfigured regarding thegroup(s) at a later time. For example, if the number of piconets exceedsthe limit for the set of piconets, another group of bands may be addedto allow more devices to use the piconet.

[0099] Implementation of embodiments may be made without significantlycomplicating designs of piconets or devices. The bands within afrequency spectrum may all be substantially the same size, and thecenter-to-center band separation may be substantially equal orsubstantially a multiple of the smallest band separation. Also, dwelltimes for the bands and the pulse rates for the bands can besubstantially the same. Fewer oscillators may be required and piconetsand devices may have a common design.

[0100] When utilized with a multiple piconet embodiment, the use ofindividual bands within the frequency spectrum and the codes describedabove coupled with multiband can yield a piconet to piconet isolation of7 to 1. This in turn translates to around 8.5 dB in amplitude or 17 dBin power. This degree of separation may be sufficient during ordinaryusage, however, in a densely packed environment band to band bleedovercoupled with the proximity of piconets and the placement of transceiverswithin each piconet, may reduce the isolation between piconets to afigure approaching zero.

[0101]FIG. 17 illustrates just such a situation. Piconet 120 is locatedin close proximity to piconet 140. In fact, piconet 120 and piconet 140may be located in such close physical proximity that the physical areasencompassed by the transmissions of each piconet 140, 120 may overlap.This may occur, for example, if each piconet 140, 120 is being utilizedwithin two adjacent apartments in a complex.

[0102] One of the results of the close physical proximity of piconets140, 120 is that device 142 within one piconet 140 may interfere withdevice 122 within another piconet 120. This interference may occurbecause device 142 on piconet 140 is transmitting on the same band onwhich device 122 is attempting to receive. Interference may also resultfrom the physical surroundings present within, or extraneous to, eachpiconet 140, 120. For example, one device 142 on piconet 140 maytransmit on a band during one dwell period, but because of the physicalsurroundings reflections of this transmission may be present duringsubsequent dwell periods. These echoes may cause device 122 on distinctpiconet 120 attempting to receive on the same band during the next dwellperiod to drop an unacceptable number of packets.

[0103] These interference problems may also be exacerbated by theplacement of devices 142, 146, 122, 124, 126 within their respectivepiconets 140, 120. Device 122 within piconet 120 may be receiving fromanother device 124 located at the extremities of the range of piconet120. Because device 142 on another piconet 140 is transmitting in closeproximity to receiving device 122, receiving device 122 may beoverwhelmed by the signal from device 142 and drop packets transmittedfrom transmitting device 124.

[0104] One possible solution to these interference problems would be toassign separate frequencies to each piconet 140, 120. Separating thefrequency spectrum between piconets 140, 120 in this manner would allowdevices 142, 144, 146, 122, 124, 146 on piconets 140, 120 to communicatewith other devices on their respective piconets 140, 120 without muchinterference. This is inefficient, however, as the frequency spectrum isonly partially utilized by each piconet 140, 120, and in the presence ofmany piconets this approach can lead to a significant degradation ofperformance.

[0105] The codes described above may also be helpful in reducinginterference on each piconet 140, 120, and between distinct piconets140, 120, but piconets 140, 120 in close physical proximity to oneanother are most likely still going to have interference problemsresulting from echoes and multipath problems, despite the possibleorthoganality of the codes.

[0106] A better solution to these interference problems is toreestablish multiple piconet channels by temporarily moving the piconets140, 120 to different bands of the frequency spectrum. FIG. 18 is aflowchart of an embodiment of a method for mitigating interferencebetween two or more piconets. Devices on a piconet may detectinterference (STEP 1810) and characterize this interference (STEP 1820).Depending on the type of interference detected appropriate remedialaction may be taken. If the interference originates from transmissionson a distinct piconet, the piconet may cease transmitting on certainbands until interference is no longer present (STEP 1830). It will bereadily apparent to those of skill in the art that the method depictedin FIG. 18 may be used in conjunction with the codes described above toachieve an even greater effect.

[0107] During operation, device 122 on piconet 120 may detect a certainamount of interference (STEP 1810). This may be done in a variety ofways, many of which are well known in the art. One such method is thedetection of a packet error rate. Many transmissions over wirelessnetworks are accomplished using a from of packetized communication.These packets may have many formats, such as TCP/IP, X.25, Frame Relay,FDDI, IEEE 802.15.3a, etc. Piconet 120 may utilize these packets fortransmission of data between two devices 122, 124. Since the receptionand transmission of data between devices is the main purpose of mostpiconets, these packets are checked very closely. In fact, most packetsinclude some type of error correction code to validate the sequence ofbits which comprise most packets, such as FEC bits or the like.

[0108] Using these error correction codes and validation bits, device122 receiving packets on piconet 120 can determine that the packet errorrate has gone above a certain threshold, and at that point device 122can make the determination that interference has been detected. Usuallythis determination is made by communication software resident on device122. As is well known in the art, this determination may be made mostefficiently at the medium access control (MAC) layer of thecommunication protocol utilized by this communications software.

[0109] Additionally, interference may also be detected (STEP 1810) bymonitoring the bit error rate of received communication on piconet 120.Usually, on piconets, transmissions are made via a series of bits. As iswell known in the art, the reception of these bits by device 122 may beassessed, and an error rate determined for the reception of bits. Ifthis error rate exceeds a certain threshold, device 122 may determinethat interference has been detected (STEP 1810). The bit error rate maybe most efficiently determined by the physical components of device 122.

[0110] In many instances, after device 122 detects a certain thresholdlevel of interference (STEP 1810), the MAC layer of the communicationprotocol resident on device 122 will attempt to mitigate thisinterference through the use of time division multiple access (TDMA).TDMA uses time division multiplexing to attempt to reduce theinterference affecting device 122. However, in many cases utilizing TDMAdoes not alleviate the interference because TDMA relies solely onassigning time slots to different transmission streams, while in maycases the interference detected (STEP 1810) at device 122 is in thefrequency domain, and is caused by the close physical proximity ofanother device 142 transmitting on another piconet 140.

[0111] After device 122 detects interference (STEP 1810), in manyembodiments of the invention device 122 will then characterize thisinterference (STEP 1820). In order to mitigate the interference atdevice 122, the interference detected can be characterized to determinean appropriate remedy. In many cases this characterization may be doneby the MAC layer of the communication protocol. The MAC layer mayprovide channel assessment commands in order to appropriatelycharacterize the interference (STEP 1820). These channel assessmentcommands may analyze the quality and quantity of interference present ona particular band in order to make an accurate evaluation of the type ofinterference present on that band.

[0112] If it is determined that the interference detected (STEP 1810) bydevice 122 is a stationary, narrow band interference a simple solutionmay be devised, such as abandoning transmitting and receiving on thatparticular band or frequency. If, however, the interference is notconfined to a narrow frequency band, or is somewhat variable in strengthand frequency, another solution may be needed.

[0113] If device 122 detects interference (STEP 1810) and thisinterference is characterized (STEP 1820) as a shifting, variableinterference, the piconet 120 may cease transmitting (STEP 1830) oncertain bands in order to mitigate the interference between piconets120, 140. Additionally, if abandoning the usage of certain bands by onepiconet 120 is insufficient to remedy the interference problems, bothpiconets 140, 120 may abandon certain bands to further ameliorate theinterference problem. In many embodiments of the invention, thefrequency spectrum is partitioned into bands. The codes described aboveallow each piconet 140, 120 to utilize most if not all of the bandswithin the frequency spectrum. However, when interference is detected(STEP 1810) one piconet 140 may cease transmitting on one set of thebands and the other piconet 120 may utilize this same set of bands forits transmissions. Conversely, the other piconet 120 may ceasetransmitting on another set of bands while the first piconet 140 usesthis set of bands for its transmissions. By keeping the sets of bandswithin the frequency spectrum substantially orthogonal, interferencebetween the two piconets 140, 120 may be kept to a minimum. In someembodiments of the invention, devices 142, 122 on piconets 140, 120 maycoordinate with one another and controllers 146, 126 of piconets 140,120 in order to facilitate a graceful cessation of transmissions onorthogonal sets of bands.

[0114] While it is desirable to have this coordination of frequencysharing be accomplished through actual message exchange, it is sometimesdifficult to have devices 142, 122 within different piconets 140, 120exchange messages, however briefly. An example of this situation mayoccur when dealing with secure piconets 140, 120, which will not talk todevice 142, 122 that does not have a proper authentication code. Inthese situations, it is still possible to accomplish frequency sharingwithout explicate coordinating messaging. Turning briefly to FIG. 20, asolution to the problem of frequency sharing without communicationbetween piconets 140, 120 is illustrated.

[0115] After detecting interference (STEP 1810) and characterizing thisinterference as originating with another piconet (STEP 1820) piconets120, 140 may cease transmitting on certain bands (STEP 1830). Thisapproach involve having a universally agreed to sharing policy, suchthat it will be possible to achieve sharing of the frequency spectrumwithout communication between the various piconets 140, 120 or piconetdevices 142, 144, 146, 122, 124, 126.

[0116] In this particular example, the active frequency spectrum isseparated into seven bands which are all being utilized by one piconet120 (1510—MODE 1). Another piconet 140 may be established soon after andbegin transmitting on all seven bands within the frequency spectrum inan initial attempt to coexist with the established piconet 120 throughthe use of the orthogonal codes described above. However, if theorthogonality is not adequate, both piconets 140, 120 will experienceunacceptable packet error rates and piconet 120 (the previouslyestablished piconet) will know that because piconet 120 was previouslyestablished the protocol dictates that piconet 120 cease transmitting onbands 2,3 and 5 of the frequency spectrum.

[0117] By the same token, a device 142 on piconet 140 may also detectinterference. Device 142 may detect interference of its own accord, ordevice 122 on distinct piconet 120 may boost its transmission signal tocause device 142 on piconet 140 to perceive interference. When device142 on newly arrived piconet 140 detects interference, the protocol maydictate that newly established piconet 140 cease transmitting on bands1, 4, 6 and 7. Now incumbent piconet 120 may utilize bands 1, 4, 6 and 7while newly arrived piconet 140 utilizes bands 2, 3 and 5 (1520—MODE 2).In this way interference between two piconets 140, 120 in closeproximity may be mitigated. Both piconets 140, 120 may continue tomonitor the bands that they have surrendered in order to detect lack oftransmissions on these bands. For example, if piconet 120 ceasestransmissions altogether, piconet 140 may be detect the lack of activityand begin transmitting on bands 1, 4, 6 and 7 once again.

[0118] The surrendering of these bands may be accomplished in a widevariety of different methods which will be readily apparent to those ofskill in the art. One method may be device 122 on piconet 120 signalingcontroller 126 of piconet 120 that interference has been detected, thepiconet controller 126 may in turn signal other devices 122, 124 onpiconet 120 that they are to cease transmitting on certain bands of thefrequency spectrum, and may utilize only certain other bands of thespectrum. Additionally, device 120 may cease transmitting on these bandsunilaterally.

[0119] With two piconets 140, 120 sharing the frequency spectrum(1520—MODE 2), suppose a third piconet is now established. At thatpoint, the two existing piconets 140, 120 experience an unacceptabledecline in their packet error rate and devices on these piconets 140,120 may detect interference from this third piconets. The existingpiconets realize they are at MODE 2 (1520) in the universal sharingpolicy, and the policy may dictate that at this point the oldestexisting piconet 120 surrender bands 4 and 7 leaving it with bands 1 and6. The policy may further dictate that the other piconet 140 at mode 2surrender band 3, and may now transmit on 2, 5 and 7, while the newlyestablished piconet may utilize bands 4 and 3 (1530 MODE 3). Thepre-agreed transition sequence assures that an acceptably equitabledistribution is achieved and that the entire spectrum is effectivelyutilized by assigning substantially orthogonal bands of the frequencyspectrum to different piconets 120, 140. It will be appreciated by thoseof ordinary skill in the art that many policies may be utilized for theassigning and distribution of bands of a frequency spectrum betweenpiconets 120, 140, it will be further appreciated that thesemethodologies may be practiced with any different number of bands andpiconets 120, 140, and may be utilized with the codes described above.

[0120] Though a universal sharing policy mitigates interference betweenpiconets 120, 140 effectively, it is sometimes desirable to coordinatebetween piconets 120, 140 which bands will be allocated to each piconetand the associated administrative details. FIG. 19 illustrates just sucha situation. In this case, two device 142, 144 on piconet 140 are insuch close proximity to device 122 on piconet 120, that they areinterfering with device 122. Device 122 may perceive this interferenceand begin to institute the universal sharing policy described above.However, it may be the case in this situation that devices 142, 144 arein such close proximity to one another during communication that theycannot detect interference from device 122 on piconet 120, even in thecase where device 122 drastically increases the power of its signal.

[0121] Under these circumstances, device 122 on piconet 120 maycommunicate with any device 142, 144, 146 on piconet 140 in order tocoordinate which sets of bands each piconet 140, 120 should cease using.In many circumstances the agreed upon protocol may mirror theuniversally agreed upon protocol discussed above, however, as oneskilled in the art will appreciate any number of schemes may beconcocted and agreed upon by the devices 142, 144, 146, 122, 124, 126within piconets 140, 120. For example, if piconet 140 is experiencinglow usage it may indicate it only requires usage of one band within thefrequency spectrum and will cease transmitting on all other bands,conversely piconet 120 may utilize all other bands within the spectrum,but must abandoned one band for use by piconet 140.

[0122] In one embodiment of the invention extensions may be made to theMAC layer of the IEEE's “802.15.3a Wireless Personal Area Network”standard in order to facilitate this communication between piconets 102,140. In particular, new MLME primitives may be added to allowcommunication between devices on distinct piconets. One examplemodifications that may be made to the MLME primitives are as follows:

[0123] 802.15.3a MAC Supplements to Support Frequency DivisionalMultiple Access

[0124] Extensions to 820.15.3 Information Elements

[0125] Dev Capability

[0126] New Information Elements

[0127] Bands Allowed

[0128] Band Report

[0129] Extensions to MLME Primitives

[0130] MLME-SCAN.confirm

[0131] MLME-Start.request

[0132] Extensions to Support Piconet Parameter Change

[0133] Piconet Parameter Change Information Element

[0134] MLME-PICONET-PARM_CHANGE Primitive

[0135] New MLME Primitives

[0136] MLME-BAND-ASSESSMENT

[0137] MLME-BAND-COORDINATION

[0138] MLME-BAND-ALLOCATION

[0139] MLME-REMOTE-BAND-ALLOCATION

[0140] MLME-REMOTE-BAND-ASSESSMENT

[0141] MLME-BAND-REPORT

[0142] MLME-LINK-STATUS

[0143] New MAC Command Frames

[0144] Band Coordination

[0145] Band Allocation

[0146] Remote Band Assessment

[0147] Link Status

[0148] Extensions Information Element Dev Capabilities Field ofCapability IE bits: b23-b16 B15 b14 b13-b11 Reserved Will Band Will BandSupported Bands¹ Allocate Coordinate b10 b9 b8 b7-b5 b4-b0 Listen toListen to Always awake Preferred Supported multicast Source fragmentModulations² size

[0149] New Information Elements Bands Allowed IE Octets: 2 1 1 BandsAllowed Length (=2) Element ID Bands Allowed Bits: 15 b14 b13 b12 b11b10 b9 b8 BAS f(15) f(14) f(13) f(12) f(11) f(10) f(9) b7 b6 b5 b4 b3 b2b1 b0 f(7) f(6) f(5) f(4) f(3) f(2) f(1) f(0)

[0150] Band Assessment Status (BAS)

[0151] Set indicates all bands have been assessed

[0152] Clear indicates all bands have not been assessed

[0153] f(x) bit set means that band is allowed in the piconet

[0154] If BAS set band is allowed based on assessment

[0155] If BAS clear band is allowed based on PNC capability only

[0156] Controlled by PNC based on assessment of band performance

[0157] Required in every beacon Band Report Octets: 2 . . . 2 2 1 1Band-n . . . Band-2 Band-1 Length = (2 * n) Element Report Report ReportID Info Info Info Band Report Info Octets: 1 1 CBAResult CBABand

[0158] Probe Rules

[0159] PNC may request and may respond

[0160] DEV may request of PNC and may respond to PNC

[0161] DEV shall not request and shall not respond to DEV other than PNC

[0162] Extensions to MLME Primitives

[0163] MLME-SCAN.confirm

[0164] Add BandsAllowed to the Piconet Description Set

[0165] MLME-Start.request

[0166] Add BandsAllowed

[0167] Extension to Support Piconet Parameter Change

[0168] Piconet Parameter Change Information Element

[0169] Add change type encoding for Bands Allowed

[0170] Allow super frame timing field to be interpreted as new BandsAllowed for this type Bits: 15 b14 b13 b12 b11 b10 b9 b8 BAS f(15) f(14)f(13) f(12) f(11) f(10) f(9) b7 b6 b5 b4 b3 b2 b1 b0 f(7) f(6) f(5) f(4)f(3) f(2) f(1) f(0)

[0171] Necessary only when Bands Allowed is changed because a band isbeing dis-allowed

[0172] All DEVs automatically drop any dis-allowed bands from their datastreams when change goes into effect—mno band coordination is requiredfor dropping dis-allowed bands

[0173] MLME-PICONET-PARM-CHANGE Primitive

[0174] Same as above

[0175] MLME Primitives

[0176] MLME-BAND-ASSESSMENT

[0177] Request

[0178] BandList—2 octets, bit set indicates request for assessment Bits:15 b14 b13 b12 b11 b10 b9 b8 BAS f(15) f(14) f(13) f(12) f(11) f(10)f(9) b7 b6 b5 b4 b3 b2 b1 b0 f(7) f(6) f(5) f(4) f(3) f(2) f(1) f(0)

[0179] BandScanDuration

[0180] 1 octet, 0-65535 usec

[0181] Confirmation

[0182] NumberOfBands

[0183] 1 octet Octets: 1 1 . . . 1 1 Worst Band Worst Band Best BandBest Band CBAR Index CBAR Index

[0184] BandRatingList

[0185] variable octets

[0186] ResultCode

[0187] 1 octet ResultCode Indication 0 Success 1 Request Denied 2Invalid Bands 3 to 255 Reserved

[0188] MLME-BAND-COORDINATION

[0189] Request

[0190] TrgtID—1 octet

[0191] BandList

[0192] Same format as for MLME-BAND-ASSESSMENT, bit set is a request tosignal on that band, if b3 is set b4 is ignored

[0193] StreamList—n octets

[0194] Indication

[0195] OrigID—1 octet

[0196] BandList—2 octets

[0197] StreamList—n octets

[0198] Response

[0199] OrigID—1 octet

[0200] ResultCode—1 octet

[0201] BandList—2 octets

[0202] If ResultCode is 0 or 4 BandList is ignored

[0203] If ResultCode is 1, 2 or 3 BandList indicates disallowed orunusable band(s) ResultCode Indication 0 Band coordination successful 1Band(s) not supported 2 Band(s) not allowed 3 Band unusable 4 Invalidstream(s) 5 to 255 Reserved

[0204] Confirmation

[0205] TrgtID—1 octet

[0206] ResultCode—1 octet

[0207] BandList—2 octets

[0208] Origin DEV will transmit using the coordinated new bands in thesuperframe in which a reception of a MLME-BAND-COORDINATION.Confirmation with a successful Result Code

[0209] Origin DEV will immediately stop transmitting with a disallowed,according to Bands Allowed Information Element in PNC beacon, regardlessof any previously successful coordination

[0210] Similarly, the Target DEV will immediately stop attempting toreceive on any disallowed bands

[0211] MLME-BAND-ALLOCATION

[0212] Request

[0213] BandList

[0214] same format as for MLME-BAND-ASSESSMENT, bit set is a request toreceive allocation of that band

[0215] AllocationDuration—2 octets

[0216] Number of superframes the Target will not use the band(s)

[0217] Indication

[0218] OrigID—1 octet

[0219] BandList—2 octets

[0220] AllocationDuration—2 octets

[0221] Response

[0222] OrigID—1 octet

[0223] ResultCode—1 octet

[0224] Confirmation

[0225] ResultCode—1 octet

[0226] MLME-REMOTE-BAND-ALLOCATION

[0227] Request

[0228] TrgtID

[0229] BandList

[0230] same format as for MLME-BAND-ASSESSMENT, bit set is a request toreceive allocation of that band

[0231] AllocationDuration—2 octets

[0232] Number of superframes the Target will not sue the band(s)

[0233] Indication

[0234] OrigID—1 octet

[0235] TrgtID—1 octet

[0236] BandList—2 octets

[0237] AllocationDuration—2 octets

[0238] Response

[0239] OrigID—1 octet

[0240] TrgtID—1 octet

[0241] ResulstCode—1 octet

[0242] Confirmation

[0243] TrgtID—1 octet

[0244] ResultCode—1 octet ResultCode Indication 0 Band AllocationSuccessful 1 Allocation duration denied 2 Band allocation denied 3Invalid Request

[0245] MLME-REMOTE-BAND-ASSESSMENT

[0246] Request

[0247] TrgtID

[0248] BandList—2 octets, bit set indicates request for assessment Bits:15 b14 b13 b12 b11 b10 b9 b8 BAS f(15) f(14) f(13) f(12) f(11) f(10)f(9) b7 b6 b5 b4 b3 b2 b1 b0 f(7) f(6) f(5) f(4) f(3) f(2) f(1) f(0)

[0249] RemoteScanTimeout

[0250] 1 octet, 0-65535 usec

[0251] Indication

[0252] OrigID

[0253] BandList

[0254] MLME-REMOTE-BAND-ASSESSMENT

[0255] Response

[0256] OrigID

[0257] NumberOfBands

[0258] BandRatingList

[0259] ResultCode Octets: 1 1 . . . 1 1 Worst Band Worst Band Best BandBest Band CBAR Index CBAR Index

[0260] Confirmation

[0261] TrgtID

[0262] 1 octet

[0263] NumberOfBands

[0264] 1 octet

[0265] BandRatingList

[0266] variable octets ResultCode Indication 0 Success 1 Request Denied2 Invalid Bands 3 to 255 Reserved

[0267] MLME-LINK-STATUS

[0268] Request

[0269] TrgtID

[0270] LinkStatusTimeout, 0-65535 usec

[0271] Indication

[0272] OrigID\

[0273] Response

[0274] OrigID

[0275] SampleWindowSize

[0276] NumberOfBands

[0277] ReceiverGain

[0278] BandQualityList octets: 1 . . . 1 Band n LQI . . . Band 1 LQI

[0279] Confirmation

[0280] TrgtID

[0281] SampleWindowSize, 0-65535 usec

[0282] NumberOfBands

[0283] BandQualityList

[0284] ReceiverGain

[0285] ResultCode

[0286] Success, Timeout

[0287] MAC Command Frames

[0288] Band Coordination request octets: n 2 2 2 StreamList BandListLength (=2+n) Command Type

[0289] Same encoding as for MLME-BAND-COORDINATION.request

[0290] Band coordination response octets: 2 1 2 2 BandList ResultCodeLength (=3) Command Type

[0291] Same encoding as for MLME-BAND-COORDINATION.response

[0292] Band allocation request octets: 2 2 2 2 AllocationDurationBandList Length (=4) Command Type

[0293] Band allocation response octets: 1 2 2 ResultCode Length (=1)Command Type

[0294] Remote band allocation request octets: 2 2 1 2 2AllocationDuration BandList TrgtID Length Command (=5) Type

[0295] Remote band allocation response octets: 1 1 2 2 ResultCode TrgtIDLength (=2) Command Type

[0296] Remote Band Assessment

[0297] Request octets: 2 2 2 BandList Length (=2) Command Type

[0298] BandList Bits: 15 b14 b13 b12 b11 b10 b9 b8 BAS f(15) f(14) f(13)f(12) f(11) f(10) f(9) b7 b6 b5 b4 b3 b2 b1 b0 f(7) f(6) f(5) f(4) f(3)f(2) f(1) f(0)

[0299] f(n) bit set requests assessment

[0300] Response octets: 2*n 1 2 2 BandRatingList Reason Code Length(=1+2*n) Command Type

[0301] BandRatingList Octets: 1 1 . . . 1 1 Worst Band Worst Band BestBand Best Band CBAR Index CBAR Index

[0302] ResultCode Value Indication 0 Success 1 Request Denied 2 InvalidBands 3 to 255 Reserved

[0303] Link Status Request octets: 1 2 2 Stream index Length (=1)Command Type Response octets: 2*n 1 2 2 2 Band Receiver Sample LengthCommand Quality List Gain Window Size (=2+2*n) Type

[0304] BandQualityList octets: 1 . . . 1 Band n LQI . . . Band 1 LQI

[0305] Support from Supplements

[0306] Band Selection

[0307] Based on capability and requirements

[0308] Based on network interference as measured by PNC and/or alldevices in the Network

[0309] Based on coexistence as measured by PNC and/or all devices in thenetwork

[0310] Based on link performance between source and target DEVs

[0311] Based on spectrum sharing

[0312] Using these extensions a device 122 on piconet 120 maycommunicate with another piconet 140 in order to coordinate the divisionand usage of the bands of a frequency spectrum. The message sequencechart for this coordination process is depicted in FIG. 21. A device 122may detect interference from another piconet 140 (STEP 1810). Device 122can then disassociate from the piconet 120 to which it belongs. Thisdisassociation process is depicted in FIG. 23. Device 122 may thenassociate with the interfering piconet 140. This association process isdepicted in FIG. 24.

[0313] Returning now to FIG. 21, after associating with the interferingpiconet 140, initiating device's DME layer sends a request to thedevice's MLME to request certain channels be freed up 2010 using MLMEband allocation primitives. This request is then forwarded on to piconet140 with which device 122 is now associated using MAC layer bandallocation commands 2020. This request presents a list of bands whichinitiating device 122 wants freed, along with a time for which thesebands should remain free. When piconet 140 receives this request theMLME layer of piconet controller 146 indicates to its DME that a requestfor certain bands has arrived using MLME band allocation primitives2030.

[0314] In turn, piconet controller's 146 DME responds to the MLME usingthe same MLME band allocation primitives indicating that those bands areto be freed up for the duration requested 2040. The piconet controller146 of interfering piconet 140 will then respond to device 122 using MACband allocation commands indicating that device's 122 request has beengranted 2050. Device's 122 MLME then confirms this grant to its DMEusing MLME band allocation primitives 2060.

[0315] After this exchange between device 122 and interfering piconet140, device 122 may disassociate from interfering piconet 140 andassociate with its original piconet 120 (See FIGS. 22 and 23). Device122 can then coordinate with piconet 120 to use the bands whichinterfering piconet 140 has relinquished. The message sequence chart forthis coordination is depicted in FIG. 22.

[0316] Initiating device's DME layer sends a request to the device'sMLME to request the use of certain channels agreed upon with interferingpiconet 140 using MLME band allocation primitives 2110. This request isthen forwarded on to the piconet 120 with which device 122 is nowassociated using MAC layer band allocation commands 2120. This requestpresents the list of bands which interfering piconet 140 has agreed tofree, the associated stream list, along with a time for which thesebands and streams should remain free. When piconet 120 receives thisrequest the MLME layer of piconet controller 126 indicates to its DMEthat certain bands and streams have been freed for a certain durationusing MLME band allocation primitives 2130.

[0317] In turn, piconet controller's 126 DME responds to the MLME usingthe same MLME band allocation primitives indicating that those bands areto be utilized for the duration indicated 2140. The piconet controller126 of piconet 120 will then respond to device 122 using MAC bandallocation commands indicating that device's 122 request has beenreceived, acknowledged, and granted 2150. Device's 122 MLME thenconfirms this grant to its DME using MLME band allocation primitives2160. After the expiration of the duration for which the bands werefreed, interfering piconet 140 may return to transmitting on the grantedbands. Piconet 120 can either wait to detect interference to coordinatewith interfering piconet 140 again, or may preemptively enter intocoordination with interfering piconet 140 before expiration of theduration for which the bands have been granted.

[0318] While a focus of the specification has been RF communicationsbetween devices using a piconet, the concepts are not limited to theembodiments described herein. The concepts may be applied to anycommunicating medium where communications are to be made between devicesusing electromagnetic radiation (including optical, ultraviolet,infrared, etc.) at discrete bands within a frequency spectrum.

[0319] In the foregoing specification, the invention has been describedwith reference to specific embodiments. However, one of ordinary skillin the art appreciates that various modifications and changes can bemade without departing from the scope of the present invention as setforth in the claims below. Accordingly, the specification and figuresare to be regarded in an illustrative rather than a restrictive sense,and all such modifications are intended to be included within the scopeof present invention.

[0320] Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any element(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature or element of any or all the claims.

What is claimed is:
 1. A method, comprising mitigating interferencebetween piconets including: detecting interference between a firstpiconet and a second piconet; and ceasing transmission on a first set ofbands wherein the first piconet ceases transmission by at least one of aplurality of devices on the first set of bands and the second piconetcontinues to utilize the first set of bands.
 2. The method of claim 1,further comprising ceasing transmission on a second set of bands whereinthe second piconet ceases transmission by at least one of anotherplurality of devices on the second set of bands and the first piconetcontinues to utilize the second set of bands.
 3. The method of claim 1,wherein ceasing transmission on the first set of bands is done for apredetermined time period.
 4. The method of claim 3, wherein the firstset of bands and the second set of bands are substantially orthogonal.5. The method of claim 4, wherein the first set of bands and the secondsets of bands substantially encompass a time coded frequency spectrum.6. The method of claim 1, further comprising monitoring the first set ofbands for activity, wherein the first set of bands is monitored by thefirst piconet.
 7. The method of claim 6, further comprising resumingtransmission by at least one of the plurality of devices on one or moreof the bands in the first set of bands when no activity is detected onone or more bands within the first set of bands.
 8. The method of claim1, wherein detecting interference includes evaluating an error rate. 9.The method of claim 8, wherein the error rate is a bit error rate andthe evaluation is done at the physical layer.
 10. The method of claim 8,wherein the error rate is a packet error rate and the evaluation is doneat the medium access control layer.
 11. The method of claim 1, furthercomprising attempting to mitigate interference through the use of timedivision multiple access when interference is detected.
 12. The methodof claim 1, further comprising characterizing interference wheninterference is detected.
 13. The method of claim 12, whereincharacterizing includes channel assessment done in the physical layer.14. A method, comprising mitigating interference between piconets,including: detecting interference between a first piconet and a secondpiconet; communicating between the first piconet and the second piconet,wherein the communication includes establishing a first set of bands anda second set of bands; and ceasing transmission on the first set ofbands wherein the first piconet ceases transmission by at least one of aplurality of devices on the first set of bands and the second piconetcontinues to utilize the first set of bands.
 15. The method of claim 14,further comprising ceasing transmission on a second set of bands whereinthe second piconet ceases transmission by at least one of anotherplurality of devices on the second set of bands and the first piconetcontinues to utilize the second set of bands.
 16. The method of claim14, wherein ceasing transmission on the first set of bands is done for apredetermined time period.
 17. The method of claim 14, furthercomprising keeping a history, wherein the first piconet keeps track ofthe sets of bands.
 18. The method of claim 17, wherein establishing thefirst set of bands takes into account the history.
 19. The method ofclaim 18, wherein the first set of bands and the second set of bands aresubstantially orthogonal.
 20. The method of claim 19, wherein the firstset of bands and the second sets of bands substantially encompass a timecoded frequency spectrum.
 21. The method of claim 14, further comprisingmonitoring the first set of bands, wherein the first set of bands ismonitored by the first piconet.
 22. The method of claim 21, furthercomprising resuming transmission by at least one of the plurality ofdevices on one or more of the bands in the first set of bands when noactivity is detected on one or more bands within the first set of bands.23. The method of claim 14, wherein detecting interference includesevaluating an error rate.
 24. The method of claim 23, wherein the errorrate is a bit error rate and the evaluation is done at the physicallayer.
 25. The method of claim 23, wherein the error rate is a packeterror rate and the evaluation is done at the medium access controllayer.
 26. The method of claim 14, further comprising attempting tomitigate interference through the use of time division multiple accesswhen interference is detected.
 27. The method of claim 14, furthercomprising characterizing the interference when interference isdetected.
 28. The method of claim 27, wherein the characterizingincludes channel assessment done in the physical layer.
 29. A tangibleelectronic media, comprising a program for mitigating interferencebetween piconets, including instructions translatable for: detectinginterference between a first piconet and a second piconet; and ceasingtransmission on a first set of bands wherein the first piconet ceasestransmission by at least one of a plurality of devices on the first setof bands and the second piconet continues to utilize the first set ofbands.
 30. The tangible electronic media of claim 29, further includinginstructions translatable for ceasing transmission on a second set ofbands wherein the second piconet ceases transmission by at least one ofanother plurality of devices on the second set of bands and the firstpiconet continues to utilize the second set of bands.
 31. The tangibleelectronic media of claim 29, wherein ceasing transmission on the firstset of bands is done for a predetermined time period.
 32. The tangibleelectronic media of claim 31, wherein the first set of bands and thesecond set of bands are substantially orthogonal.
 33. The tangibleelectronic media of claim 32 wherein the first set of bands and thesecond sets of bands substantially encompass a time coded frequencyspectrum.
 34. The tangible electronic media of claim 29, furtherincluding instructions translatable for monitoring the first set ofbands and the second set of bands for activity, wherein the first set ofbands is monitored by the first piconet.
 35. The tangible electronicmedia of claim 34, further including instructions translatable forresuming transmission by at least one of the plurality of devices on oneor more of the bands in the first set of bands when no activity isdetected on one or more bands within the first set of bands.
 36. Thetangible electronic media of claim 29, wherein detecting interferenceincludes evaluating an error rate.
 37. The tangible electronic media ofclaim 36, wherein the error rate is a bit error rate and the evaluationis done at the physical layer.
 38. The tangible electronic media ofclaim 36, wherein the error rate is a packet error rate and theevaluation is done at the medium access control layer.
 39. The tangibleelectronic media of claim 29, further including instructionstranslatable for attempting to mitigate interference through the use oftime division multiple access when interference is detected.
 40. Thetangible electronic media of claim 29, further including instructionstranslatable for characterizing interference when interference isdetected.
 41. The tangible electronic media of claim 40, whereincharacterizing includes channel assessment done in the physical layer.42. A tangible electronic media, comprising a program for mitigatinginterference between piconets, containing instructions translatable for:detecting interference between a first piconet and a second piconet;communicating between the first piconet and the second piconet, whereinthe communication includes establishing a first set of bands and asecond set of bands; and ceasing transmission on the first set of bandswherein the first piconet ceases transmission by at least one of aplurality of devices on the first set of bands and the second piconetcontinues to utilize the first set of bands.
 43. The tangible electronicmedia of claim 42, further including instructions translatable forceasing transmission on the second set of bands wherein the secondpiconet ceases transmission by at least one of another plurality ofdevices on the second set of bands and the first piconet continues toutilize the second set of bands.
 44. The tangible electronic media ofclaim 42, wherein ceasing transmission on the first set of bands is donefor a predetermined time period.
 45. The tangible electronic media ofclaim 42, further including instructions translatable for keeping ahistory, wherein the first piconet keeps track of the sets of bands. 46.The tangible electronic media of claim 45, wherein establishing thefirst set of bands takes into account the history.
 47. The tangibleelectronic media of claim 46, wherein the first set of bands and thesecond set of bands are substantially orthogonal.
 48. The tangibleelectronic media of claim 47, wherein the first set of bands and thesecond set of bands substantially encompass a time coded frequencyspectrum.
 49. The tangible electronic media of claim 42, furtherincluding instructions translatable for monitoring the first set ofbands and the second set of bands, wherein the first set of bands ismonitored by the first piconet.
 50. The tangible electronic media ofclaim 49, further including instructions translatable for resumingtransmission by at least one of the plurality of devices on one or moreof the bands in the first set of bands when no activity is detected onone or more bands within the first set of bands.
 51. The tangibleelectronic media of claim 42, wherein detecting interference includesevaluating an error rate.
 52. The tangible electronic media of claim 51,wherein the error rate is a bit error rate and the evaluation is done atthe physical layer.
 53. The tangible electronic media of claim 51,wherein the error rate is a packet error rate and the evaluation is doneat the medium access control layer.
 54. The tangible electronic media ofclaim 42, further including instructions translatable for attempting tomitigate interference through the use of time division multiple accesswhen interference is detected.
 55. The tangible electronic media ofclaim 42, further including instructions translatable for characterizingthe interference when interference is detected.
 56. The tangibleelectronic media of claim 55, wherein the characterizing includeschannel assessment done in the physical layer.
 57. An apparatus,comprising a first piconet operable to mitigate interference betweenpiconets; and a device on the first piconet operable to detectinterference between the first piconet and a second piconet, wherein thefirst piconet is further operable to cease transmission by at least oneof a plurality of devices on a first set of bands and continuetransmitting on a second set of bands.
 58. The apparatus of claim 57,further comprising a device on the second piconet operable to detectinterference between the first piconet and the second piconet whereinthe second piconet is further operable to cease transmission by at leastone of another plurality of devices on the second set of bands andcontinue transmitting on the first set of bands.
 59. The apparatus ofclaim 57, wherein ceasing transmission on the first set of bands is donefor a predetermined time period.
 60. The apparatus of claim 59, whereinthe first set of bands and the second set of bands are substantiallyorthogonal.
 61. The apparatus of claim 60, wherein the first set ofbands and the second sets of bands substantially encompass a time codedfrequency spectrum.
 62. The apparatus of claim 57, wherein the firstpiconet is further operable to monitor the first set of bands and thesecond set of bands for activity, wherein the first set of bands ismonitored by the first piconet.
 63. The apparatus of claim 62, whereinthe first piconet is further operable to resume transmission by at leastone of the plurality of devices on one or more of the bands in the firstset of bands when no activity is detected on one or more bands withinthe first set of bands.
 64. The apparatus of claim 57, wherein detectinginterference includes evaluating an error rate.
 65. The apparatus ofclaim 64, wherein the error rate is a bit error rate and the evaluationis done at the physical layer.
 66. The apparatus of claim 64, whereinthe error rate is a packet error rate and the evaluation is done at themedium access control layer.
 67. The apparatus of claim 57, wherein thefirst piconet is further operable to attempt to mitigate interferencethrough the use of time division multiple access when interference isdetected.
 68. The apparatus of claim 57, wherein the first piconet isfurther operable to characterize interference when interference isdetected.
 69. The apparatus of claim 68, wherein characterizing includeschannel assessment done in the physical layer.
 70. An apparatus,comprising a first piconet operable to mitigate interference betweenpiconets; and a device on the first piconet operable to detectinterference between the first piconet and a second piconet, wherein thefirst piconet is further operable to cease transmission by at least oneof a plurality of devices on a first set of bands and continuetransmitting on a second set of bands wherein the first set of bands andthe second set of bands are established via communication between thefirst piconet and the second piconet.
 71. The apparatus of claim 70,wherein the second piconet is further operable to cease transmission byat least one of another plurality of devices on the second set of bandsand continue transmitting on the first set of bands.
 72. The apparatusof claim 70, wherein ceasing transmission on the first set of bands isdone for a predetermined time period.
 73. The apparatus of claim 70,wherein the first piconet is further operable to keep a history, whereinthe first piconet keeps track of the sets of bands.
 74. The apparatus ofclaim 73, wherein establishing the first set of bands takes into accountthe history.
 75. The apparatus of claim 74, wherein the first set ofbands and the second set of bands are substantially orthogonal.
 76. Theapparatus of claim 75, wherein the first set of bands and the secondsets of bands substantially encompass a time coded frequency spectrum.77. The apparatus of claim 70, wherein the first piconet is furtheroperable to monitor the first set of bands and the second set of bands,wherein the first set of bands is monitored by the first piconet. 78.The apparatus of claim 77, wherein the first piconet is further operableto resume transmission by at least one of the plurality of devices onone or more of the bands in the first set of bands when no activity isdetected on one or more bands within the first set of bands.
 79. Theapparatus of claim 70, wherein detecting interference includesevaluating an error rate.
 80. The apparatus of claim 79, wherein theerror rate is a bit error rate and the evaluation is done at thephysical layer.
 81. The apparatus of claim 80, wherein the error rate isa packet error rate and the evaluation is done at the medium accesscontrol layer.
 82. The apparatus of claim 70, wherein the first piconetis further operable to attempt to mitigate interference through the useof time division multiple access when interference is detected.
 83. Theapparatus of claim 70, wherein the first piconet is further operable tocharacterize the interference when interference is detected.
 84. Theapparatus of claim 83, wherein the characterizing includes channelassessment done in the physical layer.